Signaling via mitogen-activated protein kinase kinase (MEK1) is required for Golgi fragmentation during mitosis.
We have developed an assay using permeabilized cells to monitor fragmentation of the Golgi complex that occurs during mitosis. Golgi stacks, in permeabilized interphase normal rat kidney (NRK) cells, upon incubation with mitotic extracts undergo extensive fragmentation, and the fragmented Golgi membranes are dispersed throughout the cytoplasm. We find that the continued presence of p34cdc2, the mitosis initiation kinase, is not necessary for Golgi fragmentation. Instead, fragmentation depends on cytosolic mitogen-activated protein kinase kinase 1 (MEK1 or MAPKK1). However, the known cytoplasmic substrates for MEK1, ERK1, and ERK2 are not required for this process. Interestingly, we find a Golgi-associated ERK, which we propose as the likely target for MEK1 in Golgi fragmentation.
Acharya
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U
Department of Biology, University of California, San Diego, La Jolla 92093-0347, USA.
Mallabiabarrena
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Acharya
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JK
Malhotra
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D000818:Animals; D016203:CDC2 Protein Kinase / Q000502:physiology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000502:physiology; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D003600:Cytosol / Q000201:enzymology; D004072:Digitonin / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006056:Golgi Apparatus / Q000201:enzymology / Q000502:physiology*; D007425:Intracellular Membranes / Q000201:enzymology; D007668:Kidney; D048369:MAP Kinase Kinase 1; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D008938:Mitosis / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism* / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D015398:Signal Transduction / Q000502:physiology
D004791:Enzyme Inhibitors; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D016203:CDC2 Protein Kinase; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D004072:Digitonin